Photo Quiz #29 Answer
By Jim Burns
Because we don’t see shorebirds on any kind of a regular basis here in land-locked Arizona, we become attuned every fall (remember July/August is “fall” on the shorebird calendar) to using our big scopes and meticulously detailed field guides to focus on darting, wheeling flocks of tiny peeps. Cursory glances and uninformed expectations for our larger, easier to identify long-legged waders may lead us to miss or misidentify some beautiful, fascinating, and rare migrant shorebirds. Let’s tune into them with this quiz.
A) Good photo, easy bird
Well, this is certainly no peep. This is a large shorebird with rather plain, unmarked plumage but a visually spectacular structure. The structural features that leap from the image are the obviously long legs and the amazingly long, scimitar shaped bill which appears jointed or notched at the tip.
Few of our North American bird species are as aptly named as the Long-billed Curlew and, given a head profile such as we have here, few are as readily recognizable. Long-billed Curlew is our largest shorebird, some females measuring over two feet in length, the bill itself nearly a foot long. The name “curlew” comes to us from the French imitation of their haunting, two syllable flight call, and the genus name, Numenius, comes from the Greek word for new moon, crescent shaped like the curlew’s decurved bill.
There are, nonetheless, some identification caveats. Curlews are often seen feeding in wet pastures or flooded fields at distances great enough that bill length and shape might not be readily discernible. In these situations or in the case of a sleeping bird with bill tucked under a wing or at rest against its back, body size and plumage may suggest Whimbrel or Marbled Godwit. Additionally, be aware that juvenile Long-billeds, seen in the fall, can have much shorter bills than adults and thereby in profile can easily resemble Whimbrels.
Behavioral traits dictated by structural differences can offer interesting identification clues for distant birds. Long-billed Curlews, as well as the godwits with their upturned bills, feed more by probing whereas Whimbrels tend to pick rather than probe. The length of the bill and the flexibility of its seemingly jointed tip allow Long-billed Curlews to angle deeply into the soft sediment burrows of crustaceans and worms and open the bill underground to capture these prey items. Think of the tip of this marvelous bill as an inverted spoon capable of tactiley locating food and scooping it toward the tongue.
Long-billed Curlews are fairly common migrants through the agricultural fields south and west of Phoenix in both spring and fall, often in flocks of a dozen of more birds. Pairs have been observed in Arizona grasslands during breeding season, but nesting has not yet been documented. This Long-billed Curlew was photographed at the Gila Farms catfish ponds October 25, 1992.
B) Good photo, difficult bird
Here is another long legged wader with an outstanding bill, this one slightly upturned and, like that of our curlew, longer than the bird’s head. Birds that might qualify on these two structural criteria are American Avocet, Greater Yellowlegs, Willet, or any of our godwits. Let’s eliminate avocet because this bill is neither thin enough nor upturned enough, and this plumage is mottled and cryptic rather than bold lights and darks. Eliminating the others on our list cannot be done quite so readily.
The thick, slightly upturned bill of Greater Yellowlegs, lighter at its base, looks to be a good match for our quiz bird’s, and yellowlegs will show the dark loral line between eye and bill that we see here. But did we mention that yellowlegs have yellow legs? Even in black and white, there is no shade of yellow that would appear as dark as these legs. Furthermore, our quiz bird’s plumage is also too dark, particularly on the belly which in all ages of yellowlegs is white or off-white. Despite the boldly marked scapulars and dark flank streaking which might define breeding plumaged Greater Yellowlegs, these legs are not yellow and this is not a yellowlegs.
Willet presents another interesting possibility, assuming of course you don’t see the beautiful black and white Willet wing pattern of the bird in flight which would clinch the identification. The Willet bill is about half again the length of its head and it is straight. “Long” and “straight” are relative and at a distance can be hard to judge. This close-up profile, though, shows a bill twice the length of the bird’s head, and the upturn is noticeable. In breeding plumage, Willets’ scapulars are finely spotted and barred and there is thin flank barring against a white belly—not a description of our photo bird.
Long, thick, and upcurved does describe the bill of our four North American godwits. Bar-tailed, a coastal species, and Black-tailed, an Asian vagrant, have not been recorded in Arizona and are not expected. Marbled Godwit is expected, both spring and fall, and is listed as an “uncommon transient” in Birds of Phoenix and Maricopa County. It is our largest godwit, nearly the size of a Long-billed Curlew, and so similar in plumage that at a distance, without the proper sight angle of the curlew’s sickle shaped bill, the two species can and are often mistaken for one another.
Like Long-billed Curlews, Marbled Godwits appear mottled brown above with fine white speckling and buffy below, with cinnamon wing linings and an unstreaked head. In breeding plumage Marbled Godwits show fine, dark barring on the cinnamon belly, but juveniles passing through in the fall have the same plain, unmarked underparts as Long-billed Curlew. The bill is bright, salmon pink with a dark tip.
What’s wrong with this picture? Well, it doesn’t fit the above description. What we see in this picture is a godwit bill on a bird that is boldly spotted above with conspicuously wide barring on very dark underparts—a breeding adult, not a juvenile, not a bird expected in the fall, not really a bird expected in Arizona at all. This Hudsonian Godwit was photographed at the Willcox ponds in May, 1996, at that time only the fourth state record, all during spring migration.
C) Bad photo, easy bird
Many generally accepted principles of good photographic technique take flight when the subject is birds, done in by the unpredictability of that subject. Composition is the most obvious of these and leads to a paraphrasing of the standard aphorism of photographic excellence--“f/8 and be there.” With birds it becomes “f/8 and be lucky.” You can learn to use your camera and you can learn to find the birds, but you can’t learn lucky. Look how pleasing the composition of the first two images is compared to that of our third subject which unluckily happened to be standing in front of a busy background which partially obscured its bill shape and head markings. And if you move to change positions for a cleaner background, this guy is on his way to Siberia.
Structurally this bird resembles our curlew though neither the long decurved bill nor the long legs appear to be quite curlew length. Most noticeable, however, are two outstanding plumage differences. The white mottling on this bird’s dark upperparts is heavier and bolder than that of the curlew, and this bird has a bold head pattern--thin white central crown stripe defined by thick dark stripes over a light supercilium.
Whimbrel is our only large wader with these bold crown stripes. It is longer bodied than Long-billed Curlew and thus has a sleeker, more streamlined jizz. In migration it is less common in Arizona than Marbled Godwit and, though not unexpected, the flock of 213 noted in a field near Yuma last April certainly expanded the limits of those expectations. This Whimbrel was photographed at the Sisson Road mudflats near Painted Rock Dam after the floods along the Gila in July of 1993.
Though typically easier to identify, Arizona’s large shorebirds are generally less common and also less approachable than the little peeps we’ve come to love and curse as we stand in the mud with our scopes and field guides. Save some time this fall to seek out and savor these long-legged beauties and their eye-catching structural anomalies.